The present invention relates to a reflecting surface shape measuring method, a reflecting surface shape measuring unit, a position control method, a stage unit, an exposure apparatus, a method of making the exposure apparatus, a device, and a method of manufacturing the device and, more particularly, to a shape measuring method and shape measuring unit for the reflecting surface of a reflecting mirror provided for a moving object such as a stage, a position control method using the shape information of the reflecting surface measured by the shape measuring method, a stage unit for controlling the position of a sample mounted thereon by the position control method, an exposure apparatus which controls the position of a mask or substrate by the position control method, a method of making the exposure apparatus, a microdevice manufactured by using the exposure apparatus, and a method of manufacturing the microdevice.
In a lithography process for manufacturing a semiconductor element, liquid crystal display element, or the like, an exposure apparatus has been used. In such an exposure apparatus, patterns formed on a mask or reticle (to be generically referred to as a xe2x80x9creticlexe2x80x9d hereinafter) are transferred through a projection optical system onto a substrate such as a wafer or glass plate (to be referred to as a xe2x80x9csubstrate or waferxe2x80x9d hereinafter, as needed) coated with a resist or the like. As apparatuses of this type, a static exposure type projection exposure apparatus, e.g., a so-called stepper, and a scanning exposure type projection exposure apparatus, e.g., a so-called scanning stepper are mainly used. In these types of projection exposure apparatuses, a wafer stage capable of moving two-dimensionally while holding a wafer is provided to sequentially transfer patterns formed on a reticle onto a plurality of shot areas on the wafer. In a scanning exposure type projection exposure apparatus, a reticle stage for holding a reticle can also move in the scanning direction.
In such a projection exposure apparatus, since a circuit pattern having a very minute structure is transferred onto a wafer, position control on the wafer and reticle must be accurately performed. For this accurate position control, a reflecting mirror arranged on the wafer stage or reticle stage is irradiated with a measurement beam, and the two-dimensional position of the wafer stage or reticle stage is accurately detected on the basis of the fringe pattern of interference light between the reflected light and reference light or the phase difference therebetween.
In the above two-dimensional position detection, the height position of a detection point is preferably matched with the height position of a wafer surface coated with a resist or the like, or the pattern formation surface of the reticle. However, for example, in the case of a wafer stage, as the distance (so-called working distance) between the projection optical system and the wafer stage decreases with an increase in the N.A. of the projection optical system, it is becoming difficult to arrange a reflecting mirror on the upper surface of the wafer stage. For this reason, there is proposed a technique of arranging a reflecting mirror on a side surface of a wafer stage and correcting a so-called Abbe error caused when the height position of the detection point does not coincide with the height position of a wafer surface coated with a resist or the like.
A conventional technique of correcting such an Abbe error will be described below with reference to FIGS. 23A to 23C by exemplifying the case where an Abbe error in the X direction of the wafer stage moving along the X-Y plane is corrected.
In the conventional technique, as shown in FIG. 23A, a tilt interferometer (heterodyne differential interferometer) 103 is used to detect the tilt state of a substrate table 101, i.e., the rotation amount of a reflecting surface 102S of a reflecting mirror (plane-parallel plate mirror) 102 around the Y-axis, which is arranged on one side surface of the substrate table 101 and extends along the Y-axis direction.
In the tilt interferometer 103, two light beams which are emitted from a light source unit (not shown), slightly differ in their wavelengths, and are polarized in orthogonal directions are incident on a polarizing beam splitter 105 to be split into two light beams in accordance with each polarizing direction. A light beam LU that is deflected by the polarizing beam splitter 105 and propagates in the +Z direction is reflected by a reflecting prism 106. This light beam is then incident on the reflecting surface 102S (the Z position of the incident point=ZA) and reflected. Note that the tilt interferometer 103 shown in FIGS. 23A to 23C uses the double-pass scheme. The light beam LU reflected by the reflecting prism 106 is reflected twice by the reflecting surface 102S via a polarizing beam splitter 107U for double-pass branching and a quarter-wave plate 108U. The light beam LU reflected in this manner propagates toward a light-receiving unit (not shown) via the quarter-wave plate 108U, polarizing beam splitter 107U, reflecting prism 106, and polarizing beam splitter 105.
In the mean time, a light beam LL that is transmitted through the polarizing beam splitter 105 and propagates in the +X direction passes through a half-wave plate 109, and then strikes a polarizing beam splitter 107L for double-pass branching. Subsequently, like the light beam LU, the light beam LL strikes two points (each having Z position=ZB(=ZAxe2x88x92D)) on the reflecting surface of the reflecting mirror 102 via the polarizing beam splitter 107L, a xcex/4 plate 108L, and the like. Thereafter, the light beam sequentially passes through the xcex/4 plate 108L, polarizing beam splitter 107L, half-wave plate 109, and polarizing beam splitter 105 and propagates toward the light-receiving unit (not shown) along almost the same optical path as that of the light beam LU.
The light input to the light-receiving unit is therefore the composite light of the light beams LU and LL. In the light-receiving unit, the light beams LU and LL are made to interfere with each other, with their polarizing directions being matched with each other, to generate interference light reflecting the optical path length difference between the light beams LU and LL, thereby measuring the interference light. Therefore, the tilt interferometer 103 can be used to monitor the rotation state of the reflecting surface of the reflecting mirror 102 around the Y-axis with reference to the reset state of the tilt interferometer 103, i.e., the rotation state of the substrate table 101 around the Y-axis.
Consider a case where the rotational angle of the reflecting surface 102S of the reflecting mirror 102 around the Y-axis direction is 0xc2x0 while the tilt interferometer 103 is in the reset state, and a wafer W has a taper angle xcex8 in the X direction, as shown in FIG. 23B. In this case, in an exposure apparatus having an autofocus system for detecting the Z position of the surface of the wafer W and its rotations around the X- and Y-axes and matching an exposure area on the surface of the wafer W with the image plane of a projection optical system, the substrate table 101 is rotated through the taper angle xcex8 around the Y-axis in accordance with the observation result obtained by the autofocus system. With this operation, the surface of the wafer W is matched with the image plane of the projection optical system. As shown in FIG. 23C, however, there is an offset between the actual X position of each point on the surface of the wafer W and the X position of the corresponding point on the surface of the wafer W which is obtained from the corresponding X position on the substrate table 101 which is obtained by an X position detection interferometer using the reflecting mirror 102. This positional offset (Abbe error) xcex94XA is given by
xcex94XA=Lxc2x7xcex8xe2x80x83xe2x80x83(1)
where L is the difference between the Z position on the surface of the wafer W and the Z position obtained by performing X position measurement on the substrate table 101 with, for example, Z position=ZA.
When the substrate table 101 is rotated through the taper angle xcex8 around the Y-axis, an output value from the tilt interferometer 103 indicates that the optical path length is Dxc2x7xcex8, and the optical path length difference Dxc2x7xcex8 is obtained from the output value from the tilt interferometer 103. If, therefore, distances D and L are known, the Abbe error xcex94XA can be given by
xcex94XA=((Dxc2x7xcex8)/D)xc2x7Lxe2x80x83xe2x80x83(2)
By correcting the Abbe error obtained in this manner, a pattern formed on the reticle can be accurately transferred onto the wafer.
As described above, in the prior art, Abbe errors are corrected on the premise that the reflecting surface of a reflecting mirror is perfectly flat. It is, however, impossible to make the reflecting surface of a reflecting mirror perfectly flat; undulations or curls are inevitably present on the reflecting surface of the reflecting mirror.
For this reason, for example, as shown in FIG. 24A, even if the rotational angle of the substrate table 101 around the Y-axis is 0xc2x0 at the reset position of the tilt interferometer 103, and the wafer W has no tapered portion, the reflecting surface 102S of the reflecting mirror 102 is rotated around the Y-axis, as shown in FIG. 24B, due to the undulations or curls of the reflecting surface 102S of the reflecting mirror 102. In this case, letting xcex8xe2x80x2 be the tilt angle with respect to the Z-axis, the output value from the tilt interferometer 103 indicates that the optical path length difference is Dxc2x7xcex8xe2x80x2. That is, the measurement result obtained by the tilt interferometer 103 will mislead an operator into believing that the substrate table 101 is rotated through the angle xcex8xe2x80x2 around the Y-axis.
As a result, if the position of the wafer W is corrected within the X-Y plane by an Abbe error xcex94XAxe2x80x2(={(Dxc2x7xcex8xe2x80x2)/D}xc2x7L), the position of the wafer W is offset accordingly, as shown in FIG. 24C. Therefore, a pattern formed on the reticle can not be accurately transferred onto the wafer.
It is expected that a deterioration in position control precision due to erroneous recognition of Abbe errors caused by undulations or curls of a reflecting mirror will accelerate owing to an increase in the length of the reflecting mirror due to an increase in the size of the stage accompanying an increase in the size of a wafer. This may become a factor that interferes with an increase in exposure precision that is required with a reduction in transfer pattern size. This applies to a reticle stage (a reticle stage in a scanning exposure apparatus using the step-and-scan scheme, in particular). Therefore, demands have arisen for new techniques associated with high-precision position control on a stage.
The present invention has been made in consideration of the above situation, and its first object is to provide a shape measuring method and a shape measuring unit which accurately measure the shape of a reflecting surface formed on an moving object such as a stage to perform high-precision position control on a sample mounted on the moving object such as a stage.
It is the second object of the present invention to provide a position control method which can perform high-precision position control on a moving object, including correction of Abbe errors.
It is the third object of the present invention to provide a stage unit which can accurately control the position of a sample mounted thereon.
It is the fourth object of the present invention to provide an exposure apparatus which can perform pattern transfer and improves exposure precision by accurately controlling the position of a mask or substrate.
It is the fifth object of the present invention to provide a device on which a fine pattern is accurately formed and a method of manufacturing the device.
According to the first aspect of the present invention, there is provided a shape measuring method of measuring a shape of a reflecting surface which is formed on a moving object moving along a reference plane perpendicular to a first axis and extends along a second axis direction perpendicular to the first axis direction, characterized in that a one-dimensional shape of the reflecting surface in the second axis direction is measured at least at two positions in the first axis direction while the moving object is moved along a third axis direction which is perpendicular to the first axis direction and is not perpendicular to the second axis direction.
According to this method, the shape of the reflecting surface is measured by measuring the one-dimensional shapes of the reflecting surface in the direction along the second axis, in which the reflecting surface extends, at least at two positions in the first axis direction. Even if, therefore, the reflecting surface formed on the moving object undulates or curls, the shape of the reflecting surface which is required to correct the position or posture of the moving object, including the Abbe errors, can be measured.
According to the shape measuring method of the present invention, in the one-dimensional shape measurement, for example, a plurality of measurement light beams are incident on different positions on the reflecting surface along a plane parallel to the reference plane while the moving object is moved along the second axis direction, and the local rotational angle of the reflecting surface around the first axis can be sequentially measured on the basis of the light beams reflected by the reflecting surface. However, the reflecting surface as a measurement target rotates/vibrates around the first axis due to the rotation/vibration (yawing) of the moving object upon movement of the moving object along the second axis direction. Such rotation/vibration affects measurement on the local rotational angle of the reflecting surface around the first axis, resulting in an error in one-dimensional shape measurement.
In the measuring method of the present invention, therefore, preferably, in measuring the one-dimensional shape, a plurality of light beams composing a first set of measurement light beams are incident, along a plane parallel to the reference plane, onto different positions on the reflecting surface in the second axis direction while the moving object is moved in the third axis direction, and on the basis of that reflection light, a local rotation amount of the reflecting surface around the first axis is measured in accordance with a moving position of the moving object; and at almost the same time, a second set of measurement light beams composed by a plurality of light beams in the third axis direction which are apart from each other in a direction different from the first axis direction along a plane parallel to the reference plate and propagate in the third axis direction are incident onto a reflecting unit attached to the moving object, and on the basis of that reflection light a rotation amount of the moving object around the first axis is measured.
According to this method, since the second set of measurement light beams are incident on the reflecting unit from the same axis direction as the moving direction of the moving object and kept incident on almost the same positions of the reflecting unit, the yawing amount of the moving object from the state at the start of measurement can be accurately measured. Therefore, by correcting (removing) the yawing amount of the moving object almost simultaneously measured from the local rotation amount of the reflecting surface around the first axis by using the first set of measurement light beams, the local rotation amount of the reflecting surface around the first axis due to the shape of the reflecting surface can be accurately obtained. This makes it possible to accurately measure the one-dimensional shape of the reflecting surface. In this case, the second set of measurement light beams can include two light beams apart from each other along a direction perpendicular to the first axis direction and third axis direction.
In the above case, the first set of measurement light beams can include two light beams perpendicular to the reflecting surface (to be referred to as xe2x80x9ctwo-beam shape measurementxe2x80x9d hereinafter). In addition, the first set of measurement light beams may include three light beams which are arranged at different intervals and perpendicular to the reflecting surface, and a rotation amount of the moving object around the first axis and a local rotation amount of the reflecting surface around the first axis may be measured every time the moving object is moved in the third axis direction by a distance corresponding to a difference between the intervals (to be referred to as xe2x80x9cthree-beam shape measurementxe2x80x9d hereinafter). The one-dimensional shape measurement can be performed more accurately by three-beam shape measurement than two-beam shape measurement.
In the shape measuring method according to the present invention, every time a one-dimensional shape of the reflecting surface is measured at least at two positions in the first axis direction, a two-dimensional position of a predetermined mark on the moving object within a plane parallel to the reference plane, and the measured one-dimensional shape data can be corrected on the basis of the measurement result. According to this method, for example, a heterodyne interferometer and the like are used, and reset operation is performed every time one-dimensional shape measurement is performed after the position in the first axis is changed. This makes it possible to correct offsets between the respective one-dimensional shape measurement results. Therefore, the shape of the reflecting surface can be measured with high accuracy.
According to the second aspect of the present invention, there is provided a shape measuring unit for measuring a shape of a reflecting surface which is formed on a moving object moving along a reference plane perpendicular to a first axis and extends along a second axis direction perpendicular to the first axis direction, characterized by comprising a first driving unit for moving the moving object along a third axis direction which is perpendicular to the first axis direction and is not perpendicular to the second axis direction, and a measuring unit for measuring a one-dimensional shape of the reflecting surface in the second axis direction at least at two positions in the first axis direction.
According to this unit, the measuring unit measures the shape of the reflecting surface by measuring the one-dimensional shapes in a direction along the second axis, in which the reflecting surface extends, at least at two positions in the first axis direction. Even if, therefore, the reflecting surface formed on the moving object undulates or curls, the shape information of the reflecting surface which is required to correct the position or posture of the moving object, including the Abbe errors, can be obtained.
The shape measuring unit of the present invention can be configured so that the measuring unit comprises a first measuring unit for making a plurality of light beams composing a first set of measurement light beams, along a plane parallel to the reference plane, to be incident onto different positions on the reflecting surface in the second axis direction, and measuring a local rotation amount of the reflecting surface around the first axis in accordance with a moving position of the moving object on the basis of that light reflected by the reflecting surface. In this case, since the first measuring unit measures the local rotation amount of the reflecting surface round the first axis while the first driving unit moves the moving object along the third axis direction, the one-dimensional shape of the reflecting surface can be measured.
In this case, the first measuring unit can be configured as a first laser interferometer system in which an axis perpendicular to the first and second axes serves as a measurement axis. In this case, since the local rotation amount of the reflecting surface around the first axis is measured by the laser interferometer system capable of obtaining a very accurate measurement result, the one-dimensional shape of the reflecting surface can be accurately measured.
Note that the first set of measurement light beams includes two light beams substantially perpendicular to the reflecting surface. This makes it possible to perform the above two-beam measurement. In addition, the first set of measurement light beams includes three light beams which are arranged at different intervals and perpendicular to the reflecting surface. This makes is possible to perform the above three-beam measurement.
The measuring unit can further comprise a second driving unit for relatively moving the moving object and second measuring unit in the first axis direction so as to perform one-dimensional shape measurement of the reflecting surface at different positions in the first axis direction, or an optical path changing unit for changing irradiation points of the second set of measurement light beams on the reflecting surface in the first axis direction. The use of the optical path changing unit, in particular, is effective when it is difficult to move the second measuring unit or moving object in the first axis direction in consideration of measurement precision, readjustment, the weight of the object to be moved, and the like.
The measuring unit can further comprise a second measuring unit for making a plurality of light beams forming a second set of measurement light beams, along a plane parallel to the reference plane, to be incident onto positions on the reflecting surface which differ from each other in the second axis direction and differ from the irradiation points of the first set of measurement light beams in the first axis direction, and measuring a local rotation amount of the reflecting surface around the first axis in accordance with a moving position of the moving object on the basis of that light reflected by the reflecting surface. In this case, since the second measuring unit performs one-dimensional shape measurement of the reflecting surface at a position different from a position in the first axis direction at which the first measuring unit performs one-dimensional shape measurement, the shape of the reflecting surface can be quickly measured by simultaneously operating the first and second measuring units.
In this case, the second measuring unit can be configured as a second laser interferometer system in which an axis perpendicular to the first and second axes serves as a measurement axis. In this case, since the local rotation amount of the reflecting surface around the first axis is measured by the laser interferometer system capable of obtaining a very accurate measurement result, the one-dimensional shape of the reflecting surface can be accurately measured.
The shape measuring unit of the present invention which includes the first measuring unit can be configured so that the measuring unit further comprises a third measuring unit for making a third set of measurement light beams, composed by a plurality of light beams which are apart from each other in a direction different from the first axis direction and propagate in the third axis direction, to be incident onto a reflecting unit mounted on the moving object from the third axis direction along a plane parallel to the reference plate, and measuring a rotation amount of the moving object around the first axis on the basis of that light reflected by the reflecting unit.
According to this unit, the third measuring unit can measure the rotation amount (yawing amount) of the moving object around the first axis at almost the same time when the first measuring unit measures the local rotation amount of the reflecting surface around the first axis. Therefore, the local rotation amount of the reflecting surface around the first axis due to the shape of the reflecting surface can be obtained very accurately by correcting the yawing amount of the moving object measured almost simultaneously by the third measuring unit in accordance with the local rotation amount of the reflecting surface around the first axis measured by the first measuring unit. This makes it possible to measure the one-dimensional shape of the reflecting surface very accurately.
In this case, the second measuring unit can be configured as a first laser interferometer system in which the third axis serves as a measurement axis. In this case, since a yawing amount is measured by the laser interferometer system capable of obtaining a very accurate measurement result, the one-dimensional shape of the reflecting surface can be accurately measured.
Note that the third set of measurement light beams can include two light beams apart from each other in a direction perpendicular to the first axis direction and third axis direction. In this case, since a necessary minimum number of measurement light beams are used, the arrangement of the second measuring unit can be simplified.
In addition, as the reflecting unit, a reflecting mirror or a plurality of cube corner prisms can be selected.
According to the third aspect of the present invention, there is provided a position control method, for a moving object which moves along a reference plane and has a reflecting surface, characterized in that at least one of a position and posture of the moving object is controlled on the basis of shape information of the reflecting surface measured by the shape measuring method of the present invention, two-dimensional position information of the moving object measured by using the reflecting surface, and tilt information of the reflecting surface. In this case, the xe2x80x9ctilt informationxe2x80x9d is measurement information about the rotation of the reflecting surface around the axis (second axis) along which the reflecting surface extends, i.e., information before correction using the shape information of the reflecting surface. For example, xe2x80x9ctilt informationxe2x80x9d is obtained from the difference between the position measurement results, with respect to the ideal orthogonal direction to the reflecting surface, at a plurality of different positions in the normal direction (first axis direction) of the reference plane on the reflecting surface. Note that xe2x80x9ctilt informationxe2x80x9d in the specification will have the above meaning.
According to this method, since at least one of the position and posture of the moving object is controlled on the basis of the shape information of the reflecting surface measured by the shape measuring method of the present invention, the two-dimensional position information of the moving object, and the tilt information of the reflecting surface, accurate control can be performed.
According to the fourth aspect of the present invention, there is provided a stage unit for moving a sample along a reference plane perpendicular to a first axis, characterized by comprising a sample table on which the sample is mounted and which has a reflecting unit including at least one reflecting surface extending along a second axis direction perpendicular to the first axis direction; a driving unit for driving the sample table along the reference plane; and a two-dimensional position detection system for irradiating the reflecting unit with two-dimensional position detection light beams and detecting a two-dimensional position of the sample table on the basis of light beams reflected by the reflecting unit; a tilt detection system for irradiating the reflecting surface with at least two tilt detection light beams that are not in the same plane and are parallel to the reference plane and detecting a tilt amount of the reflecting surface with respect to the reference plane on the basis of light beams reflected by the reflecting surface; the shape measuring unit defined in claims 7 to 19, which measures a shape of the reflecting surface; a storage unit for storing shape information of the reflecting surface measured by the shape measuring unit; and a control system for controlling at least one of a position and posture of the sample table by controlling the first driving unit on the basis of two-dimensional position information detected by the two-dimensional position detection system, tilt information detected by the tilt detection system, and the shape information.
According to this unit, since at least one of the position and posture of the sample table is controlled on the basis of the shape information of the reflecting surface which is measured by the shape measuring unit of the present invention and stored in the storage unit, the two-dimensional position information detected by the two-dimensional position detection system, and the tilt information detected by the tilt detection system, at least one of the position and posture of the sample mounted on the sample table can be accurately controlled.
In the stage unit of the present invention, the driving unit can be configured to be used as a first driving unit in the shape measuring unit. In this case, since there is no need to prepare a separate driving unit for the shape measuring unit, the overall arrangement of the stage unit can be simplified.
In the stage unit of the present invention, the two-dimensional position detection light beams are two light beams that are vertically incident on the reflecting surface along a plane parallel to the reference plane, and the two light beams are used to measure a local rotation amount of the reflecting surface around the first axis in the shape measuring unit. This makes it possible to perform the above two-beam measurement. In addition, the two-dimensional position detection light beams are two light beams which are vertically incident on the reflecting surface along a plane parallel to the reference plane, the two light beams and one of the tilt detection light beams are three light beams which are arranged at different intervals and vertically incident on the reflecting surface along a plane parallel to the reference plane, and the three light beams are used to measure a local rotation amount of the reflecting surface around the first axis. This makes it possible to perform the above three-beam measurement.
According to the fifth aspect of the present invention, there is provided an exposure apparatus for transferring a pattern formed on a mask mounted on a mask stage onto a substrate mounted on a substrate stage, characterized by comprising the shape measuring unit of the present invention, which defines at least one of the mask stage and the substrate stage as a moving object; a two-dimensional position detection system for irradiating a reflecting unit, which is mounted on the moving object and includes the reflecting surface, with two-dimensional position detection light beams, and detecting a two-dimensional position of the moving object on the basis of light beams reflected by the reflecting unit; a tilt detection system for irradiating the reflecting surface with at least two tilt detection light beams that are not in a plane and are parallel to the reference plane, and detecting a tilt amount of the reflecting surface with respect to the reference plane on the basis of light beams reflected by the reflecting surface; and a control system for controlling at least one of a position and posture of the moving object on the basis of shape information of the reflecting surface measured in advance by the shape measuring unit, two-dimensional position information detected by the two-dimensional position detection system, and tilt information detected by the tilt detection system.
According to this apparatus, since at least one of the position and posture of the mask stage or substrate stage is controlled on the basis of the shape information of the reflecting surface formed on at least one of the mask stage and substrate stage, which is measured in advance by the shape measuring unit of the present invention, the two-dimensional position information detected by the two-dimensional position detection system, and the tilt information detected by the tilt detection system, the position or posture of the mask or sensitive sample can be accurately controlled, and a pattern formed on the mask is transferred onto a substrate mounted on the substrate stage. This makes it possible to improve the exposure precision.
According to the sixth aspect of the present invention, there is provided an exposure apparatus for transferring a pattern formed on a mask onto a substrate, characterized by comprising, a substrate table which holds the substrate and has at least two reflecting surfaces extending in intersecting directions; a driving system for driving the substrate table; a two-dimensional position detection system for irradiating at least two reflecting surfaces with measurement light beams and detecting a two-dimensional position of the substrate table on the basis of light beams reflected by the reflecting surfaces; a tilt detecting system for irradiating at least one of at least two reflecting surfaces with at least two tilt detection light beams that are not in the same plane and are parallel to the reference plane, and detecting a tilt amount of the reflecting surface with respect to the reference plane on the basis of light beams reflected by the reflecting surface; the shape measuring unit of the present invention, which measures a shape of a reflecting surface facing the tilt detection system; a storage unit for storing shape information of the reflecting surface facing the tilt detection system, which is measured by the shape measuring unit; and a control system for controlling the shape measuring unit and also controlling at least one of a position and posture of the substrate table on the basis of two-dimensional position information detected by the two-dimensional position detection system, tilt information detected by the tilt detection system, and the shape information.
According to this apparatus, since at least one of the position and posture of the substrate table is controlled on the basis of the shape information measured in advance by the shape measuring unit of the present invention, the two-dimensional position information detected by the two-dimensional position detection system, and the tilt information detected by the tilt detection system, at least one of the position and posture of the sensitive sample can be accurately controlled, and a pattern formed on the mask is transferred onto a substrate mounted on the substrate stage. This makes it possible to improve the exposure precision.
In the second exposure apparatus of the present invention, the driving unit can be used as a first driving unit in the shape measuring unit. In this case, there is no need to prepare a separate driving unit for the shape measuring unit, the overall arrangement of the exposure apparatus can be simplified.
In addition, the measurement light beams applied on the reflecting surface facing the tilt detection system are two light beams which are vertically incident on the reflecting surface facing the tilt detection system along the reference plane, and the two light beams are used to measure a local rotation amount of the reflecting surface around a first axis in the shape measuring unit. This makes it possible to perform the above two-beam measurement. In addition, the measurement light beams applied on the reflecting surface facing the tilt detection system are two light beams which are vertically incident on the reflecting surface facing the tilt detection system along the reference plane, the two light beams and one of the tilt detection light beams are three light beams which are arranged at different intervals and vertically incident on the reflecting surface facing the tilt detection system along a plane parallel to the reference plane, and the three light beams are used to measure a local rotation amount of the reflecting surface around a first axis in the shape measuring unit. This makes it possible to perform the above three-beam measurement.
The second exposure apparatus of the present invention can be configured such that the apparatus further comprises a mark detection system for detecting a position of a mark formed on at least one of the substrate table and the substrate, and the control system corrects a one-dimensional shape measurement result of the reflecting surface on the basis of a position detection result on the mark obtained by the mark detection system. In this case, since the offset between the respective one-dimensional shape measurement results on the respective reflecting surfaces can be corrected, the shape of each reflecting surface can be measured very accurately.
In the second exposure apparatus of the present invention, at least two reflecting surfaces can be two surfaces perpendicular to each other. In addition, a substrate mount surface of the substrate table can have a triangular shape, and at least two reflecting surfaces can be respectively formed on at least two side surfaces of the substrate table.
The second exposure apparatus of the present invention can be configured so that the apparatus further comprises a leveling detection system for detecting a position of the surface of the substrate in a direction perpendicular to the reference plane and a tilt of the surface with respect to the reference plane, and the control system controls a posture of the substrate table and a position of the substrate table in a direction perpendicular to the reference plane on the basis of leveling information detected by the leveling detection system, and also controls a position of the substrate table within the reference plane on the basis of two-dimensional position information detected by the two-dimensional position detection system, tilt information detected by the tilt detection system, and the shape information. In this case, in control with six degrees of freedom for the position and posture of the substrate table, control with three degrees of freedom is performed on the posture of the substrate table and its position in a direction perpendicular to the reference plane on the basis of the leveling information detected by the leveling detection system, and control with three degrees of freedom is performed on the two-dimensional position and yawing of the substrate table on the basis of the two-dimensional position information detected by the two-dimensional position detection system and the shape information. In addition, correction control can be performed on Abbe errors associated with the two-dimensional position of the substrate table.
According to the seventh aspect of the present invention, there is provided a method of producing an exposure apparatus for transferring a pattern formed on a mask mounted on a mask stage onto a substrate mounted on a substrate stage, characterized by comprising the first step of providing the shape measuring unit of the present invention, which uses at least one of the mask stage and the substrate stage as a moving object; the second step of providing a two-dimensional position detection system for irradiating a reflecting unit, which is mounted on the moving object and includes the reflecting surface, with two-dimensional position detection light beams, and detecting a two-dimensional position of the moving object on the basis of light beams reflected by the reflecting unit; the third step of providing a tilt detection system for irradiating the reflecting surface with at least two tilt detection light beams within a plane parallel to the reference plane, and detecting a tilt amount of the reflecting surface with respect to the reference plane on the basis of light beams reflected by the reflecting surface; and the fourth step of providing a control system for controlling at least one of a position and posture of the moving object on the basis of shape information of the reflecting surface measured in advance by the shape measuring unit, two-dimensional position information detected by the two-dimensional position detection system, and tilt information detected by the tilt detection system. According to this method, the first exposure apparatus of the present invention can be produced by mechanically, optically, and electrically combining various components, e.g., a mask stage, substrate stage, shape measuring unit, two-dimensional position detection system, tilt detection system, and control system, and adjusting the resultant structure.
According to the eighth aspect of the present invention, there is provided a method of producing an exposure apparatus for transferring a pattern formed on a mask onto a substrate, characterized by comprising, the first step of providing a substrate table which holds the substrate and has at least two reflecting surfaces extending in intersecting directions; the second step of providing a driving system for driving the substrate table; the third step of providing a two-dimensional position detection system for irradiating at least two reflecting surfaces with measurement light beams and detecting a two-dimensional position of the substrate table on the basis of light beams reflected by the reflecting surfaces; the fourth step of providing a tilt detecting system for irradiating at least one of at least two reflecting surfaces with at least two tilt detection light beams that are not in the same plane and are parallel to the reference plane, and detecting a tilt amount of the reflecting surface with respect to the reference plane on the basis of light beams reflected by the reflecting surface; the fifth step of providing the, shape measuring unit of the present invention, which measures a shape of a reflecting surface facing the tilt detection system; the sixth step of providing a storage unit for storing shape information of the reflecting surface facing the tilt detection system, which is measured by the shape measuring unit; and the seventh step of providing a control system for controlling the shape measuring unit and also controlling at least one of a position and posture of the substrate table on the basis of two-dimensional position information detected by the two-dimensional position detection system, tilt information detected by the tilt detection system, and the shape information.
According to this method, the second exposure apparatus of the present invention can be produced by mechanically, optically, and electrically combining various components, e.g., a substrate stage, driving system, two-dimensional position detection system, tilt detection system, storage unit, and control system, and adjusting the resultant structure.
The method of producing the second exposure apparatus of the present invention can further include the eighth step of providing the a mark detection system for detecting a position of a mark formed on at least one of said substrate table and the substrate. In this case, an exposure apparatus can be produced, in which the offsets caused between the respective one-dimensional shape measurement results on the respective reflecting surfaces can be corrected, and the shape of each reflecting surface can be measured very accurately.
The method producing the second exposure apparatus of the present invention can further include the ninth step of providing a leveling detection system for detecting a position of a surface of the substrate in a direction perpendicular to the reference plane and a tilt of the surface with respect to the reference plane. In this case, an exposure apparatus can be produced, in which in control with six degrees of freedom for the position and posture of the substrate table, correction control on Abbe errors associated with the two-dimensional position of the substrate table can be performed on the basis of the tilt information detected by the tilt detection system and the shape information.
A device having a fine pattern can be manufactured by transferring a predetermined pattern onto a substrate by exposure using the exposure apparatus of the present invention in a lithography process. According to another aspect, the present invention includes a device manufactured by using the exposure apparatus of the present invention. In addition, the present invention includes a method of manufacturing a device by transferring a predetermined pattern onto the substrate by using the exposure apparatus produced according to the making method of an exposure apparatus of the present invention in a lithography process.